fix: Use 0-based coordinates for Grid3 image resolution

Grid3 image files are named with 0-based coordinates (e.g., 1-2-0-text-0.jpeg),
but we were passing 1-based coordinates to the image resolver (x: cellX + 1, y: cellY + 1).

This caused images to fail resolving because:
- Cell at XML position X="2" Y="3" converts to cellX=1, cellY=2 (0-based)
- We passed x=2, y=3 to resolver (adding +1)
- Resolver looked for file named "2-3-0-text-0.jpeg"
- But actual file is named "1-2-0-text-0.jpeg" (0-based naming)

Fix: Pass 0-based coordinates (cellX, cellY) directly to resolver.

This fixes broken images in aac-board-viewer when viewing Grid3 gridsets
with coordinate-prefixed image names.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: willwade

examples/.DS_Store

@@ -0,0 +1,51 @@
+<FileMap xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <Entries>
+    <Entry StaticFile="Grids\Start\grid.xml">
+      <DynamicFiles>
+        <File>Grids\Start\0-1-0-text-0.png</File>
+        <File>Grids\Start\0-2-0-text-0.jpeg</File>
+        <File>Grids\Start\0-3-0-text-0.jpeg</File>
+        <File>Grids\Start\0-4-0-text-0.jpeg</File>
+        <File>Grids\Start\0-5-0-text-0.jpeg</File>
+        <File>Grids\Start\1-1-0-text-0.jpeg</File>
+        <File>Grids\Start\1-2-0-text-0.jpeg</File>
+        <File>Grids\Start\1-3-0-text-0.jpeg</File>
+        <File>Grids\Start\1-4-0-text-0.jpeg</File>
+        <File>Grids\Start\1-5-0-text-0.jpeg</File>
+        <File>Grids\Start\10-3-0-text-0.jpeg</File>
+        <File>Grids\Start\10-4-0-text-0.jpeg</File>
+        <File>Grids\Start\11-3-0-text-0.jpeg</File>
+        <File>Grids\Start\11-4-0-text-0.jpeg</File>
+        <File>Grids\Start\2-1-0-text-0.jpeg</File>
+        <File>Grids\Start\2-2-0-text-0.jpeg</File>
+        <File>Grids\Start\2-3-0-text-0.jpeg</File>
+        <File>Grids\Start\2-4-0-text-0.jpeg</File>
+        <File>Grids\Start\2-5-0-text-0.jpeg</File>
+        <File>Grids\Start\3-1-0-text-0.jpeg</File>
+        <File>Grids\Start\3-3-0-text-0.jpeg</File>
+        <File>Grids\Start\3-4-0-text-0.jpeg</File>
+        <File>Grids\Start\3-5-0-text-0.jpeg</File>
+        <File>Grids\Start\4-1-0-text-0.jpeg</File>
+        <File>Grids\Start\4-3-0-text-0.jpeg</File>
+        <File>Grids\Start\4-4-0-text-0.jpeg</File>
+        <File>Grids\Start\4-5-0-text-0.jpeg</File>
+        <File>Grids\Start\5-4-0-text-0.jpeg</File>
+        <File>Grids\Start\5-5-0-text-0.jpeg</File>
+        <File>Grids\Start\6-3-0-text-0.jpeg</File>
+        <File>Grids\Start\6-4-0-text-0.jpeg</File>
+        <File>Grids\Start\7-1-0-text-0.jpeg</File>
+        <File>Grids\Start\7-2-0-text-0.jpeg</File>
+        <File>Grids\Start\7-3-0-text-0.jpeg</File>
+        <File>Grids\Start\7-4-0-text-0.jpeg</File>
+        <File>Grids\Start\8-1-0-text-0.jpeg</File>
+        <File>Grids\Start\8-2-0-text-0.jpeg</File>
+        <File>Grids\Start\8-3-0-text-0.jpeg</File>
+        <File>Grids\Start\8-4-0-text-0.jpeg</File>
+        <File>Grids\Start\9-1.png</File>
+        <File>Grids\Start\9-2.png</File>
+        <File>Grids\Start\9-3-0-text-0.jpeg</File>
+        <File>Grids\Start\9-4-0-text-0.jpeg</File>
+      </DynamicFiles>
+    </Entry>
+  </Entries>
+</FileMap>